According to statistics, 30% of the fire occurs due to the closure of the old electrical wiring due to the unreliability of the insulation. A fire due to the fault of the electrical wiring is also possible when the electrical wiring is overloaded, which leads to overheating of the insulation and a possible short circuit and ignition of the insulation.
Full protection by the RCD device against electric shock
Connecting a residual current device (RCD) circuit and an installed circuit breaker will reliably protect your apartment from fire due to outdated electrical wiring and will protect those living in an apartment or house from electric shock. The differential machine can replace the RCD and the machine, it has all the functions of the machine and the RCD. It is extremely useful to install an RCD where children are present.
The principle of operation of the RCD
The electric shock protection device works by monitoring the difference in current between the input and output of the load. If this current difference is zero, that is, the input and output current of the load is the same, the RCD will not trip. When a person accidentally touches exposed parts of the electrical wiring, current will leak through the injured person's body and the conductive floor (concrete, damp wood floor, and so on).
In this case, there will already be a difference between the input and output currents of the load, the RCD device will disconnect the network. Old electrical wiring can also leak current, due to a violation of the properties or integrity of the wire insulation. With the old wiring, the mains voltage may be disconnected by the RCD device. In this case, replacing the old electrical wiring is required.
RCD installation methods
There are two ways to install the device. The first option involves the installation of a general RCD in the wiring diagram, immediately after the meter and the machine. With one general RCD for an apartment or house, it is very difficult to find the place of current leakage through the insulation of the wires. Such a violation of insulation must be looked for throughout the apartment or cottage.
A variant of the wiring diagram with a common RCD and protective ground in a single-phase network
In this case, the RCD will de-energize the entire apartment. In another version, several RCDs are installed, separately for each direction of wiring, in the living room, kitchen, bedroom and nursery. Such a scheme of separate electrical wiring in the rooms is assembled in the switchboard in the hallway.
Several RCDs are installed in the same switchboard. This option is certainly expensive, but it has some advantages. Firstly, when the RCD is triggered, the network will be turned off only in one direction, and in the other part of the apartment the mains voltage will remain. In one room, it will be easier to look for damage to the electrical wiring.
A variant of the wiring diagram with a separate RCD for outlets and protective grounding in a single-phase network
In the children's room, a separately connected RCD device will protect children from touching a dangerous outlet faster than in the general RCD version. For the option of a children's room, an RCD with a shutdown current of less than 10 mA is installed. In the bathroom, or in the kitchen, where the washing machine is located, you need to install an RCD with a high operating current value (300mA - 500mA), because an RCD with a shutdown current of 10 mA will constantly turn off the kitchen.
RCDs are selected for the optimal current for all loads in amperes. The response time of the RCD - a high-quality device - is up to 0.1 seconds, during this time an electric shock is not felt. The protection device should be checked for operability by pressing the RCD test button once a month and after each emergency operation.
RCD connection diagram in single-phase and three-phase networks
The RCD connection diagram in single-phase and three-phase networks is almost the same. In the case of a single-phase network, an automatic machine is installed in front of the RCD, then the voltage from the RCD is supplied to the load of the entire apartment.
A variant of the wiring diagram with a separate RCD and protective grounding in a single-phase network
With a three-phase network, a circuit breaker is also installed after the electric meter for each phase separately, and an RCD is installed after the circuit breaker.
A variant of the wiring diagram with a general RCD, a separate RCD for a washing machine, a fireplace and an RCD for kitchen sockets and protective grounding in a three-phase network
You need to carefully connect the RCD circuit, you must not confuse the neutral with the phase at the RCD terminals. The device has a terminal designation (see instructions).
How to connect an RCD without grounding?
When there is no protective grounding in the apartment, then it is possible to connect the RCD to a two-wire network without deteriorating its protective parameters. Although in the PUE it is forbidden to install a common RCD in the TN-C system (ground and neutral are connected) due to a decrease in the probability of its operation by hundredths of a percent. As practice has shown, the RCD copes well with its task even without protective grounding.
Connection diagram for RCD without grounding
However, the choice is yours, for me it is better to put an RCD without grounding than to be left without protection, or install a protective ground loop. RCD protection circuitry, quickly triggers when current passes through the human body, a possible short circuit (in this case, an automatic switch or differential automatic device must be installed) and when current leaks through the old insulation of the wiring.
